This invention relates to a supporting device for a picture tube, for example, used in a television set, and particularly to a device which is particularly useful when the space for the picture tube is limited and the tube is exposed to vibration.
Recently, the performance of color picture tubes has developed so markedly, that the conventional mono-chrome picture tube is used only for special purposes or when cheapness is the only requirement. When changing a monochrome picture tube to a color picture tube, it is desirable to position the latter within the same space as provided for the former. Accordingly it has been necessary to minimize the size of the mounting parts in order to fit the tube within a certain space.
FIG. 1 shows a general construction of a conventional color picture tube schematically. The picture tube 1 comprises a panel 2 having a fluorescent screen on its inner surface, a funnel 3, and a neck 4 including an electron gun (not shown), with all said members being in a single body. A metal band 5 for the purpose of preventing implosion is wound around the outer surface of the panel 2, and a fitting member 6 for mounting the tube 1 extends outside of the band 5, and the member is secured to the band 5 with some of its portions interposed between the band 5 and panel 2. Accordingly dimension D in FIG. 1 is comparatively large in spite of the fact that dimension d is not so large.
Furthermore, in the conventional device, the transmission of vibration from outside to the tube is not prevented or absorbed. A shadow mask 7 is suspended in front of the fluorescent screen of the panel 2 by means of leaf springs (not shown) fixed to the inner side surface of the panel 2. This shadow mask 7 is exposed to resonance vibration at certain frequencies caused by vibration transmitted from outside through the fitting 6. In an extreme case, the shadow mask 7 is vibrated by some hundreds of .mu.m, causing the electron beams, and therefore the shadows of the shadow mask, to be shaken so that undesirable chromatic aberration is induced.